Filter and the method of making the same



an. 30, 1940. L[ H, TALMAIJGE 2,188,488

FILTER AND THE METHOD OF MAKING THE SAME Original Filed May 18, 1938 I(Ittorneg Patented Jan. 30, 1940 8 FILTER AND METHOD OF MAKING THE SAMELouis H. Talmadge, Wethcrsfield, Conn., assignor, by mesne assignments,to The Silex Company, Hartford, Conn., a corporation of ConnecticutContinuation of application Serial No. 208,648, May 18, 1938. Thisapplication May 11, 1939,

Serial No. 273,018

12 Claims.

This invention relates to filters and the method of making the same andis particularly intended for such filters as are used in connection withcoffee makers of the vacuum type. The present invention comprises aspecific embodiment of the invention set forth in U. S. patent toBiberthaler, et al., No. 3,123,327, July 12, 1938, and this applicationis a continuation of the application filed by me May 18, 1938, SerialNo. 208,648.

A filter of this class is usually constructed from a disc of suitablematerial which is applied over a button shaped drainer plate and securedthereto .by means of an'elastic member which draws the edges of saidfilter beneath the plate. The said elastic member is secured along theedges of the disc to draw it into the form of a pouch which may bereadily applied to and retained in its proper position over the drainerplate. Heretofore, such elastic members have, in some cases, beensecured adjacent to and along the edge of the disc by means of a row ofstitches within which the said members are encased and allowed to slip.In other cases, the said mem-' bers have consisted of a number ofelastic strands contained within a woven flexible cover ing and havebeen secured to the disc by a row of stitches extending through. thecover and parallel to the strands. In each of said cases, it has beenfound that, upon breaking, the said elastic members will slip, bycontraction, away from their position relative to the filter and therebybecome inefiective for drawing the surrounding edges of the discinwardly thereon.

An object of this invention therefore is to provide a filter for coffeemakers having an elastic member which is secured adjacent to and alongthe edge thereof in such a manner that, even if it should become brokenat one or more points, it will still remain effective to function asintended; the said object being attained by providing the said elasticmember in the form of a single elastic band and sewing the same directlyto the drainer by means of a row of stitches so that each of saidstitches will secure the corresponding portion of the elastic member infixed position with relation to the corresponding portion along theperiphery of thedisc.

A further object of this invention is the provision of an improvementover the method, disclosed in the co-pending application to Wesley R.Becher, Serial No. 193,905 filed March 4, 1938, for Strainers and themethod of making the same, for producing filters of the class describedherein Other objects and advantages of this invention will be clearlyunderstood from the following description and from the accompanyingdrawing in which:

Figure 1 is a view of the apertured side of the filter pouch embodied inmy invention.

Figure 2 is an edge view of the same as shown in Figure 1. j

Figure 3is an enlarged sectional view on line 3-3- of Figure 1.

Referring to the drawing, the particular pouch.

illustrated includes a piece of material 5 which is originally cut inthe shape of a flat disc and then contracted into a pouch by gathers 6that are formed in the marginal portion of the disc; the free edge 1 ofwhich becomes the aperture defining edge of the pouch.

The said gathers are formed in the process of securing an elastic strip8 upon one face of the 'margin by means of an over-edge stitch 9sometimes called overseaming. Preferably this stitch comprises two ormore interlooped threads, one of which, as indicated at I0, penetratesthe material of the disc to anchor the stitching over the said freeedge.

In obtaining the objects of this invention, the said stitching isextended through both, the material of the pouch and the elastic member8, to secure and maintain the latter in superimposed relation to oneface of the gathered marginal and to enclose the free edge of themathereto from manipulation, the thread penetrations in the strip arepreferably located adjacent to the edge-l l, which is most remote fromthe stitch enclosed edge of the pouch.

As shown, the elastic strip 8 preferably comprises a piece of suitablelength applied uponthe ,pouch'with its ends overlapping and secured asat' 8, in superimposed relation upon one face of the gathered marginal,by the over-edge stitching as above described. I

While this blank piece of material, from which the pouch illustrated isformed, is preferably circular, the same may be of any shape suitable toform the desired pouch when the marginal portion of the blank iscontracted.

The said elastic strip may be of a rubber material known as lastex or ofany other suitable material.

The method of making the said filter preferably consists of forming thefilter material into a blank in the shape of a disc, then placing themarginal portion of said disc into a suitable sewing machine, withthestrip of elastic material super-imposing said marginal portion, andapplying the over-edge stitch to secure said strip to the disc as abovedescribed; said sewing machine being especially adapted to gather thesaid marginal portion of the disc under the said elastic strip, as itapplies the over-edge stitch therethrough, by the provision of what isknown as a difierential feed, which will feed the material of the discthrough the machine faster than the elastic strip is superimposedthereon; thereby gathering the marginal portion of the disc under thesaid elastic strip as they pass through the machine and just before thestitching is applied through the strip and gathered margin.

The character of the over-edge stitch used is such that it permitsconsiderable expansion in the longitudinal direction along the marginalportion and thus provides for expansion of the aperture in the pouch,for application thereof to the button shaped drainer plate.

As will be clearly understood from the illustration in Figure 1, thesaid elasticstrip is sewn around the disc and the ends therefore may beoverlapped for a. distance, as at l2, by continuing the sewing operationover the leading end of the said' elastic strip. The said elastic stripand the thread which forms the stitches may be then cut off and the saidstrip will form a continuous elastic band which extends entirely alongthe edge of said disc and is securely fastened thereto.

It will be also understood that, should said elastic band become broken,it will not be permitted to contract into an ineffective condition forthe reason that the said stitches will retain the broken sections of theband in their respective location and will continue to function fordrawing the edge portions of the disc inwardly by closing the gatherstherein, in the same manner that the entire band will function when itis not broken.

While there is shown, in the illustration, an elastic member whichconsists solely of a rubber strip, the same may also be of any wellknown type of elastic bands and may be sewn to the strip by means of acommon form of straight stitches, if desired, without departing from thescope of my invention as set forth in the appended claims.

I claim:

1. A filter of the character described comprising a disc of perviousmaterial having an elastic strip member extending along the periphery ofsaid disc, said strip member being secured to said disc by a row ofstitches extending through said member and said disc, and the length ofsaid strip member, when in contracted condition, being substantiallyless than the circumference of said disc, whereby, when said stripmember is contracted, the said disc is drawn into the form of a pouch.

2. A filter of the character described comprising a sheet of perviousflexible material having an elastic member consisting solely of anelastic band or strip which is stitched directly to said material, alongthe edge thereof, by a row of stitches extending through said member andsheet; the length of said elastic band, when in contracted condition,being substantially less than the periphery of said sheet, whereby, whensaid elastic member is contracted, the said sheet is drawn into the formof a pouch.

3. For a coffee maker, a filter comprising asheet of pervious fabrichaving an elastic member disposed adjacent to and along the edgesthereof and secured to said sheet by means of a row of stitches whichoverlap the said edges and extend through said member and sheet; thelength of said member, when in contracted condition, being substantiallyless than the periphery of said sheet, whereby, when said member iscontracted, the said sheet is drawn into the form of a pouch.

4. For a coffee maker, a filter comprising a sheet of pervious fabricmaterial having an elastic member consisting solely of an elastic bandor strip secured adjacent to and along the edges of said sheet by meansof a row of stitches extending through said member and sheet andoverlapping the said edges to prevent the unraveling of the saidmaterial along saidedges; the length of said elastic member, when incontracted condition, being substantially less than the periphery ofsaid sheet, whereby, when said member is contracted said sheet is drawnin the form of a bag.

5. A filter of the character described comprising a disc of perviousmaterial having a flexible member consisting of an elastic band or stripwhich is substantially rectangular in cross section and sewn to saiddisc, adjacent to and along the edges thereof by a row of stitchesextending through said member and disc; the length of said member, whenin contracted condition, being substantially less than the circumferenceof said disc, whereby, when the said member is contracted, the said discis drawn into the form of a pouch.

6. A filter of the character described comprising a disc of perviousmaterial having an elastic member consisting solely of an elastic bandor strip which is substantially rectangular in cross section and sewn tosaid disc, adjacent to and along the edge thereof, .by means of a row ofstitches which extend through said band and disc, adjacent to one edgeof said band, and overlap the opposite edge of said band and the edge ofsaid disc,iwhereby, a major portion of said band is contained withinsaid stitches and the said material is prevented from unraveling alongthe edges thereof; the length of said elastic member, when in contractedcondition, being substantially less than the circumference of said disc,whereby, when the said member is contracted, the said disc is drawn intothe form of a pouch or bag.

7. A filter of the character described comprising a piece of perviousmaterial having its marginal portion contracted by gathers therein,which form tile material into a pouch, an elastic strip extendedsubstantially entirely along the gathered edge, and over-edge stitchingpassing through the strip by which the said gathered edge and one edgeof the elastic strip are enclosed.

8. A filter comprising a piece of pervious material formed into a pouchby gathers in the marginal portion of the material, a non-endlesselastic strip superimposed upon one face of and substantially entirelyalong the gathered marginal portion, and over-edge stitching passingthrough the strip and enclosing the free edge of the marginal portionand one edge of the elastic strip, a sufficient portion of the width ofthe strip being included in the'said stitching to insure maintenance ofthe strip in superimposed relation to the marginal portion,

9. The method of making a filter pouch of the character described, whichcomprises gathering the marginal portion of a piece of pervious materialto form a pouch with contracted material about its opening,superimposing an elastic strip upon one face of the gathered margin, andoverseaming the free edge of the margin and one edge of the elasticstrip substantially entirely along the gathered margin and in a mannerto maintain the strip in superimposed relation to said margin withstitching passing through said strip and material.

10. The method of making a filter pouch of the character described,which comprises simultaneously gathering the marginal portion of a pieceof pervious material, superimposing an elastic strip upon one face ofthe gathered margin and securing the said strip in superimposed relationto and substantially entirely along the gathered margin byover-stitching penetrating said elastic strip and material and overlyingthe edge of said material and one edge of said strip.

11.'The method of making a filter pouch of the character described whichcomprises gathering the marginal portion of a piece of pervious materialto form a pouch or bag with a portion of said material contracted aboutits opening, superimposing a non-endless elastic strip upon one face ofthe gathered margin, and securing the said elastic strip in superimposedrelation to and substantially entirely along the gathered margin byoverstitching to enclose the free edge of the margin and one edge of theelastic strip; the said overstitching penetrating the elastic stripadjacent to the edge thereof most remote from the free edge of themargin. 1

12. The method of making a filter of the characterdescribed from a discpervious material,

which comprises gathering the marginal, portion of said material whilesuperimposing a strip of elastic material over the said gathered marginand sewing the said elastic strip to and substantially along the saidgathered margin by means of a row of stitches passing through said strip0 and material and overlying the free edge of said margin and one edgeof said elastic strip.

LOUIS H. TALMADGE.

